In orthopedic medicine, traction refers to various mechanisms for straightening or aligning bones in a desired manner. An approach to knee osteoarthritis (OA) management involves invasive joint distraction. Experience with invasive joint distraction indicates that distracting the OA afflicted joint for an extended period may halt or reverse the disease.
Initially, joint distraction was used in the treatment of joint malalignment and joint contracture. An external fixation frame was used to actively reposition the joint and to increase the range of motion. Distraction was performed to prevent damage (compression) of the joint cartilage during the forced repositioning. In some of these patients OA was present in the treated joint and an unexpected clinical improvement of the OA was observed. These clinical observations led to a proof-of-concept study examining the benefit of joint distraction, by treating young patients with severe ankle OA. Two-thirds of patients treated for 3 months with joint distraction experienced significant clinical benefits for a period of up to 10 years. Based on preliminary radiographic outcomes in a few patients, joint distraction may lead to tissue structure modification.
Osteoarthritis can be found in other joints and there is reason to believe that distraction will have the same effect in other joints as described for the knee above. One major joint for OA is the first CMC joint (first carpal-metacarpal joint, also known as the trapeziometacarpal joint or the basal thumb joint) and OA of this joint is commonly considered thumb arthritis.
As shown in FIGS. 1 and 2, the CMC joint is where the metacarpal bone of the thumb meets the trapezium bone at the wrist. The trapezium forms a recess into which the metacarpal bone rests, and both bones are covered with cartilage. Thumb arthritis results in severe hand pain, swelling, decreased strength and range of motion, and makes routine tasks painful and difficult to achieve. Thumb arthritis is one of the most common forms of OA due in part to the significant forces the CMC joint undergoes in routine activities.
Thumb arthritis occurs when the cartilage breaks down and wears away from adjoining ends of the metacarpal and trapezium bones at the first CMC joint. In early stages of thumb arthritis, there may be inflammation about the joint and isolated breakdown of cartilage around one or a few areas of the cartilage surface. As the arthritis progresses, bone spurs may develop and the thumb may contract into the palm, with pain and mobility of the hand worsening.
Treatment of arthritis in the early stages may involve joint protection, such as through hand supports arranged to reduce thumb movement or completely immobilize the thumb. Known hand supports may be soft or hard varieties, with soft hand supports providing better freedom of movement but less immobilization, whereas hard hand supports provide superior immobilization but better pain relief. Other options for treatment of hand arthritis include conservative treatments such as joint protection, physical therapy, massage, and cold and hot therapy. For moderate to severe hand arthritis, treatment options include medicines, injections, and invasive surgical treatment including ligament reconstruction, joint replacement, and joint fusion.
Medicines may cause side effects and diminishing returns over time, merely masking the pain but failing to treat the cause of the arthritis. Injections are effective however they may lead to a weakening of the joint and result in further breakdown of cartilage since they, like medicine, do not treat the source of the arthritis. The surgical treatments, while effective in treating the source of the arthritis, are invasive and recovery from surgical treatment for a return to normal activities is time-consuming.
The CMC joint may become inflamed due to excessive motion of the joint. While immobilization of the joint can reduce pain and inflammation, it does not allow for the functional use of the joint. A dynamic stability split may be used to reduce excessive motion of the joint while serving to provide traction to the joint to treat osteoarthritis.
Therefore, there is a desire for a solution to treat moderate to severe hand arthritis in a non-invasive manner that concentrates on the source of the arthritis rather than just the pain.